thanks Bill,
others have touched on many/all of your points.
But you did a great job of logically fitting all of the pieces into a pretty convincing story.
-bill
Ok, so since this makes sense to at least two of us…
Why is there so much drama on this forum regarding Epoxy? It is great stuff of course but I am still a bit bewildered as to how it has aquired such heroic proportions.
It is a fantastic marketing coop. But I think the focus should be more on the characteristics of the overall composite structure shells and solutions they bring to the table, rather than just the resin system.
It has always kind of surprised me that Surftechs are referred to as Epoxy boards, seems there would be a more encompasing description of the technology that makes them what they are. But then just saying “Epoxy” is a pretty simple monicer that has a great positive hook to it.
Buckling boards have always been a problem but there are other simple solutions that aren’t as drastic that will decrease it.
Why is there so much drama on this forum regarding Epoxy?
cuz if there aint no drama somewhere this place might start to get a little dull…
good insight there bro…i’ve got some tests in mind…will update here when i get some spare time
Aloha Meecrafty
Some tests would be great! But I have little doubt that epoxy would win out in most cases And composite sandwich skins also.
The trick is creating better production methods so this kind of construction can leave the cheaper labor and facilities costs of the back yard world and go mainstream.
I agree with others comments that this will likely continue to push production of these kinds of boards overseas were the labor costs are cheap enough to spend the extra time it takes to make these kinds of boards.
I have a full facility here but I would be hard pressed to get excited about making sandwiched skin, styropoxy boards in it. Not cause they would be cool boards but because the economic numbers wouldn’t work out unless the boards could sell for near triple what my boards sell for now.
Thanks Bill
Another great post…
But you’re leaving us dangling…
do you go for a stiff sandwich core since your mentioning Dcell or with something soft?
And is that why Bert has found balsa to be the best compromise as a sandwich core versus something like corecell, dcell, honeycomb aluminum, carbon, bamboo, cedar, or guava?
On the other hand Jim Richardson at Surflight is wrapping his “tuned” blue foam XPS lever springs with milky white “polyproplene packing foam” with high spring memory before covering them with a skin of urethane in a completely different approach to building a sandwich board. Hard on the inside and soft on the outside.
So does the skin need to be indestructable to compensate for core failure or not?
And is this why Pope, Aviso, Halun, and Hydroepic are pursuing a different build solution than Surftech, Boardworks, XTR, and Pointblanks. I noticed that Greg has aligned himself with Halun, Wayne Rich with Pope, Jeff Johnson, Matt Bilos, and Jim Richardson are looking at Aviso and who knows what syndicate Bert’s aligned himself up with… EVryone else is just pushing their plugs…
It’s all about the skin and tissue then and not the blood…
I guess I’m surprised as big and as important as the sways community is we don’t have at least a couple PHD CHEMICAL engineers who work for DOW, or NASA guys, or other rocket scientists who actually make their living doing this stuff under the microscope of getting it right so you don’t kill off a bunch of folks versus a random grouping of tradefolks and suppliers arguing about highly technical information. There’s folks out their that do this stuff for a living, that get paid big bucks to make all the appropriate decisions regarding this stuff nationally and globally so why aren’t they here speaking up to set us it all straight…
Oh shoots I forgot again…
this is just a forum on surfer dudes talking about their surfboards…
Gotta quit snorting the acetone…
Oneula,
yeah surflight is the killer concept…very intrigued by it…would like to hear how they ride
BB,
i mostly agree but im not so sure eps would win the peel test…those beads tend to seperate quite easily…i do remember reworking a favorite board last year where i peeled the entire bottom off like a banana…ive done this to both poopee and stypoxy and the stypoxy was definitely harder to pull off…but that could of been a function of the heavier glassing…further testing required…some guys might be interested in the results…
deck countour has got to play a major role in buckling as well…convex is stiff then suddenly gives on extreme loads…corrugated might win that test
regarding your other comments…bert once said it takes him anywhere from 9 to 14 hours to make a sunova…wow i guess hes got the system down…and yeah those boards go for $800-1000 but last many times longer than poopee so evidently you get more value…wouldnt be so great for repeat biz though…kind of scary if thats what one does for a living
I think you guys have already answered each other’s questions…Bill says he’d have to charge 2-3 times as much per board to make up the increased cost…Oneula says Bert has hit upon balsa as the best sandwich core material…Meecrafty remembers the price tag on Bert’s boards…
Put it all together? First, not only is balsa a great core material, but its beautiful, eye-catching, a well-known traditional surfboard material, and has a lot of that imminently desirable ‘classic’ or ‘retro’ cachet that drives so many surfboard buyers - at least the ones with their own names on the credit card in their pocket.
So to me, half the hurdle in getting the higher price is right there in the appearance of the board. “Wow, its real balsa under there. Of course its going to cost more than just foam & glass…but its so cool, I want it anyway.”
And then the other half the hurdle - it lasts 5-10 times longer. So pay 3 times more but keep the board easliy as long as you’d keep 3 foam & glass boards? Simple math. Again, your average adult consumer can understand that. No problem.
Only last thing is, the board’s gotta work. If it doesn’t work, who cares how long it lasts - the guys not gonna want to keep it anyway.
I think manufacturers need to give their adult comsumers a little more credit. Not all of us are perpetual Peter Pans. I don’t want a chippy thruster any more than I want a giant clunky watch that tells me when my heat is over nor do I want to hang out in a “surf shop” that mainly seems to sell $100 shoes and blast lousy music to accompany corporate skateboard videos. And as if I want to even crack open a mainstream surfing magazine - its got more bullshit ads than Cosmo. But, yeah, I can do math. If a board - better looking than most - lasts longer too? I don’t really care what it costs, I’d consider buying it.
Problem is, nobody’s making me that board. So I had to learn to do it myself 
Quote:
surfboard buyers - at least the ones with their own names on the credit card in their pocket.
Good one Ben! Some times with I see in these forums I really wonder about that… This is another great one… So true…
Quote:
Problem is, nobody’s making me that board. So I had to learn to do it myself
Quote:
I think manufacturers need to give their adult comsumers a little more credit
I agree with this statement, but I think that they need to give us credit by giving us more information. I’ve noticed that my views have steadily changed the more that I understood. Its why I think that Greg and Bert are doing such a great service. They are providing information and I can decide if I accept it or not. It was the “Rich Harbor thinks …” thread that made me decide to start using epoxy.
ahh yes…
information is power!
i wouldnt have started building boards w/o the internet…sometimes i sit back and reflect…the internet…anything you want to learn is just a computer click away…simply amazing!
Bill,
Your perception of compressive strength and it’s importance is right on (so nice to hear someone who makes surfboards nail that one). Your right, many of the failures we are dealing with in surfboards today have to do with the non structural aspects of the modern blank, whether urethane, EPS or XPS and not the resin.
The real advantage to EPS/epoxy has always been the extra weight savings that the foam and resin afford that can be turned into structural re-enforcment. That’s whether it’s stringers, power rods, rail channels, extra glass or sandwich construction. A failing in the surfboard industry over the years has been the refusal to accept that there is such a thing as strength to weight. How many times have I seen a glass shop finish a 1.5 lb. EPS blank with a 4 double 4 glass job and then wonder why it falls apart. IT WEIGHS 4 POUNDS! “Yea, but that’s the way we glass everything.”
Do you know what percentage of glass shops even have a scale? Almost none. Is weight important? Is it as important as an 1/8 inch of tail rocker? Shouldn’t it be measured just like the rocker? Shouldn’t an experienced glasser be able to closely estimate the weight of a finished board given all the numbers? Does this have a relevence to strength? Why is it such a non issue among manufacturers?
Again we’re talking of the shallowness of both the manufacturers and the marketplace and Bill’s comment that, “surfers aren’t very demanding.” Therefore most surfboard builders only build product to mediocre levels. Will this will change? It already has. Surftech is the proof. Imported polyester boards have now also become acceptable and the American industry looses marketshare everyday still convinced that upgrading product or introducing an upgraded American built product can serve them.
The recent expanding market both domestically and internationally, has disquised those loses but expansion won’t be forever. In fact if history serves we’ll see a leveling off by 2009. The realization of marketshare loss could be as devestating to this American industry as it has been to so many others.
The push overseas, as I see it, has less to do with cheap labor and more to do with foreign government subsidies being given to manufacturing for export by their respective governments. Our government has issues with forcing the hands of other governments when we are guilty of giving subsidies as well (farm). Therefore the dismantling of American industry is at hand.
I’ve seen a lot of ways to produce surfboards over the years and there’s quite a bit of new technology coming out in this regard. I’m going to see something new this weekend and then again the weekend following. Building sandwich construction boards may not be such an issue in the near future.
There are ways to test the sandwich structure as a whole. There are addaptations of ASTM standards that can be used for soft/compliant core sandwich structures that would allow us give proof. The problem is is that this type of structure is not straight forward. Standard beam theory needs to be adjusted. Standard beam theory does not take into account the deformation of the core material. With a softer core, deformation does take place. The simplest addaptaion would be to add all the parts of the structure together and assume that the role of the core material is to keep the two faces at a constant distance therefore only taking into consideration the thickness of the core material. But this is not enough to really determine the strength. What this does is neglect the shearing stress in the face materials ,the normal stresses in the core material, and the shearing stresses of the core. If we want to be really picky we will also have to take into account that the Foam material is no longer uniform across the thickness since some binding material is now impregnated into both surfaces which results in a really complicated computation of the shearing modulus of the core.
There are I think seven possible modes of failure for our type of sandwich composite construction.
1 face tensile yielding
2 face compressive yielding
3 core shear
4 core tensile yield
5 core compressive yield
6 core indentation
7 core debonding from face
The majority of failures in compliant/“soft” core foam sandwich structures are due to static overloading or fatigue loading conditions which are caused by localized effects such as the application of concentrated loads (rocks, waves) at points or lines of support, and due to bending effects induced in the area of points of geometric and material discontinuities. The reason for this is because localized shearing and bending effects induce severe transverse normal and interfacial shear stresses. All of these stress components can be of significant magnitude, and in a lot of cases exceed or just meet the allowable stresses in the core material as well as in the interfaces between the core and the face sheets.
I think it is necessary to realize that talking about compliant core sandwich structure is a difficult task. For most sandwich panels (ie, metal honeycomb core/metal skin aircraft wings), analysis ignores the presence of localized effects. The general approach used to determine bending, buckling, vibration are based on an approach which replaces the layered structure with a solid homogenous object with the same properties. If this was to be used with the soft foam core model, it would disregard the compressibility of the foam core, and assumes that the boundary conditions are the same for both faces.
What that all means is the surfboard structure has a geometrically nonlinear behavior. Basically it is not straightforward and a pain, and probably why there is very little data published for diffent foam/facesheet combos. All of this and the subject of curvature (both rocker and deck contour like Meecrafty suggested) hasn’t even entered the equation.
Greg, a quick practical question. If one wanted to make a modern 9’0" longboard using epoxy resin and didn’t want it to weigh any less than a clark superblue blank with standard poly glassing (for example, a Harbour H3), would you recommend using a heavier clark blank like the classic and standard glass (but epoxy) or using a lighter eps blank and going with extra layers of glass? Which would provide the most resistance to the sort of denting and delam concerns on the deck that Rich Harbour’s test showed was more prevelant on the epoxy glassed decks: stronger foam, or more glass? Would you predict a difference in surfing feel either way? Thanks!
I like 2# density EPS. To me, for most board building that’s, all round, the best I’ve used. It resists denting as well as the lighter weight urethanes, doesn’t leak through dings and doesn’t have heat issues. For me, and how I like to build boards, urethane is just too heavy and doesn’t allow many re-enforcment options. The epoxy boards Rich built were urethane foam and came out lighter than his polyester glass jobs. This is because epoxy is lighter (by 20%) in glassing at the same schedule. This is the main reason for the denting. Weight is the constant. You can’t compare by glass schedule, you have to compare by board weight. Weight is the measurement that matters.
And 2# EPS rarely delaminates.
A 9’ longboard with 2# foam, a 6 bottom with double 6 deck weighs 11 lbs. Each successive layer then weighs 1.25 lbs. per side. So lets say the Harbour weighs 16 lbs. (probably a forgiving guess). You have 5 lbs. to add which is another 4 layers of 6 oz. which would then give you 4 on the deck and three on the bottom. Denting won’t be a problem now! If you wanted to do a gloss you could take away a bit of the glassing and add the gloss (maybe use a couple of 4’s in place of a couple of those 6’s). If the Harbour weighs more than 16 you can now figure out how to make the new board weigh what you want. By the way 4 oz. on a 9’ weighs a bit under a pound … like 7/8ths.
These schedules may seem extreme but a former poster, Noodle, used to build his boards exactly that way. I’ve also built boards like this and I’m sure they will outlive me. Talk about no dings! Many of the board builders in Texas use a triple 4, quad 4 glass schedule using S-glass. The boards come out surprisingly light and strong as hell. In FL standard glassing on longboards is double 4 and double 6 or triple 4 which gives you the 11 - 12 lb. longboard which is reasonably strong, quite durable and bitchin to ride.
Thanks for that great info Greg. It’s nice to know the weight each layer of glass will add! I’m saving that one to the hard drive!
I second that. Throwin the knowledge.
Point Blanks also makes their longboards with triple 6 bottom, triple 6 top with a 4 oz deck patch…and a finished 10’0" weighs about 17.
Slim,
The added layers I’m talking about in weight are successive layers. The first layer weighs more because you have to wet the foam and create a foundation for that first layer. This foundation layer on an EPS blank weighs about 3/4 of a lb. more than the successive layers on a 9’er. In my post above I was just adding to the basic board we build, so the foundation, fin boxes, hot coats, etc were already there. Just wanted to point that out before someone came back with a single layer weighing more than I specified.
Thanks for the clarification on the weight numbers for glassing.
Just for comparison and to know what to expect, I weighed a few boards this morning, using the not so precise method of holding them and stepping on my bathroom scale and subtracting my weight. They were also waxed so that may add a little. The results were somewhat surprising. I would have guessed they’d all be lighter than they turned out to be:
6’3"x18x2.25 Cole thruster
8lbs. - I would have guessed more like 5 or 6 since it feels like nothing in my hands.
7’ x 11 1/4" x 20 1/4" x 13 1/4" x 3 1/16" Cambell Bonzer Five
13 lbs!
7’4" x 16 3/4 x 22 7/8 x 15 1/2 x 2 3/4 Harbour Spherical Revolver
13.5 lbs.
9-0 x 16 3/4 x 21 1/4 x 13 1/2 x 2 3/4 Harbour Simms Slimmer
18 lbs.
9’0 Steve Coletta pintail custom (much wider than the simms)
20.5 lbs. but by feel in my hands i would have guessed heavier
i have three scales…one digital one pound capacity, the other two are spring/hook scales…an expensive 6lb cap chatillon and a 15 pounder bought at a fishing tackle shop…you can get something accurate (within a couple of ounces) for $25 or so…try Bass Pro Shops.com…i weigh each step in the building process and record the numbers.
those weight numbers seem a little off slim…if you have something you know weighs x amount you can use that as a control or reference sample (interesting trivia…a US dollar bill weighs exactly one gram…a nickle 5 grams…i use them to check the accuracy of my digital scale)…look for something that has a known weight…i’ve used weight barbell plates in the past…or a bunch of soup cans
8 pounds for that Cole sounds too heavy…i think the average for a chip is about 6.5 or so…Plus One can make’m down to 5.25 but they dont last long at all, according to his own comments…temporary competition boards
greg’s weight numbers jive…but you gotta really squeegee all the excess out…which is easier with warm epoxy resin…i recently did two 4oz layers on a wide 6’4 that added 1.1 pounds.
i finally got my super strong 5.5 pounder and truthfully, it was a challenge getting there the first time…but now that i have a system, i feel my next can better 5 pounds…still with better durability than poopee…havent figured out the flex thing out tho…yet
and just to re-think my previous comments…one doesnt have to be a great surfer to appreciate a lighter than normal board…i feel the faster response to turning and swinging the nose of the board around, redirectional surfing, makes one a better pocket surfer, or at least facilitates the improvement process towards more performace or progression…meaning a lighter board can definitely make one a better performance surfer
Yea, sounds like your scale may have been a bit high. Boards aren’t as light as people think though. Building a shortboard under 5 lbs is impressive as is building a londboard under around 14. When you ride a longboard in the 11-12 lb range it’s incredible. I did build one 9’ that was 7.5. I only rode it a couple times. It was sandwiched with airex and I took everything I could out of it just to see how light I could get it. Turned out to be really flexy cause the was almost no glass in it. Really was great for noseriding and only had a 16" nose. The flex helped with the noseriding more than I would have guessed. And had I built for it to be as flexy as it was it would have held up better. Turned out there were too many materials that were at odds.